It is well recognized in the health and fitness industry, that aerobic exercise should be done at regular intervals over an extended period of time in order to build up a sufficiently high level of fitness for the full benefit thereof to be obtained. Sporadic attempts at exercising are often at best only marginally effective. For various reasons ranging from disability to inconvenience many people barely exercise at all. A most common experience is the lack of time perceived as available for dedication to regular appearances at a gym or other exercise facility. Accordingly, many different types of exercise machines involving reciprocal motion, have been proposed to maximize the muscular range and intensity of exercise enabling the benefit thereof to be optimized in a minimum time period and different fitness levels to be accommodated.
For example, the prior art abounds with hand crank type exercise machines as taught by U.S. Pat. No. 3,309,084 issued Mar. 14, 1967; U.S. Pat. No. 4,222,376 issued Sep. 16, 1980; U.S. Pat. No. 4,521,012 issued Jun. 4, 1965; and U.S. Pat. No. 4,582,318 issued Apr. 15, 1986.
Each of the machines taught in the above mentioned prior patents suffers from a particular disadvantage. They may for example, be so bulky, cumbersome, complex and expensive as to deter home use. They are not portable or easily carried, restricting use to a single location, or require permanent installation, thereby reducing the opportunity for and, therefore, regularity of use even by an individual of average fitness. Furthermore, a disabled person, particularly one in a wheelchair, would be precluded from using those machines which require them to stand. The elderly, as well as pregnant women would not be advised to use these particular machines which tend to stress the lower back excessively in view of risk of strain